HUNDREDS of passengers sat for hours in grounded planes at Melbourne and Brisbane airports after their flights to Sydney were diverted because of yesterday's dust storm.A combination of gale-force crosswinds and blinding red dust forced flight delays, diversions and cancellations in the eastern states. These continued into the evening well after conditions had improved.Six flights were cancelled and 23 diverted to Melbourne and Brisbane yesterday morning. But the two airports could not cope with the extra aircraft traffic.Only a handful of aircraft were able to dock and discharge their passengers, leaving hundreds of people in stuffy, crowded aircraft cabins for up to five hours until conditions cleared enough for their flights to return to Sydney.Qantas diverted all of its Sydney-bound international flights during the storm and provided passengers with refreshments.''Melbourne and Brisbane were congested with other aircraft so most of them had to wait off-terminal,'' a spokesman said.''Two flights were able to have access to gates at Brisbane and they were provided with refreshment vouchers.''All diverted flights returned to Sydney except Cathay Pacific flight CX111 from Hong Kong, which was delayed by 13 hours after being diverted to Melbourne.''The delay caused by having to go to Melbourne because of the storm meant that the crew ran out of rest hours,'' a spokesman for Cathay Pacific Airlines, David Bell, said.''We've put the passengers up in a hotel until we can [put crew in] the aircraft again - it's just a very unfortunate situation brought about by some pretty incredible weather.''Staff at Sydney Airport said the combination of high winds and severely restricted visibility was unlike anything they had ever seen.''Low visibility is usually caused by fog which will clear as soon as you get a breath of wind,'' said a spokesman, Michael Samaras.''In this case we're getting powerful wind gusts but the same wind is bringing the dust with it.''The havoc caused by the storm in Sydney produced knock-on effects along the east coast.''Our flight from Brisbane to Sydney was delayed by four hours because of the storm and then for another hour because someone ran into the plane [with a baggage truck],'' said Ray Skillicorn, as he waited at Sydney Airport with his wife and their wheelchair-bound grandson.''We missed our connecting flight to Taipei and the next connecting flight to Canada,'' he said. ''My grandson only has a few weeks' holiday.''